wear just a trenchcoat to uni (no clothes underneath), and open it up in frnt of her at a lecture and say "how about you study this"
but srsly, there's hotties all around my classes n shit, i found easiest way to talk too them is find common ground. you kinda sit near her (2 seats away++ not next toh er) and say something like hey do u have last weeks notes or something, use something too wing your way in. you can only really start introducing yourself first weeks of uni imo without it being a bit wierd later (thats my point of view though)
id say its much easier to pick up in tutes, done it before. but randoms on the street, no idea whatsoever; never have and never will probably haha